Room heater



Oct. 4, 1949. Q Ml OSTERHELD 2,483,664

ROOM HEATER la /7/ j I N V EN TOR.

CLARK M. OSTERHELD 4 TT'Y OC- 4, 1949- c. M. OSTERHELD ROOM HEATER 2Sheets-Sheet 2 Filed Sept. 26. 1946 l I l l INVENToR.

CLARK M. osTERHl-:LD

Patented ct. 4, 1949 ROOM HEATER Clark M. Osterheld, Stoughton, Wis.,assignor to McGraw Electric Company, Elgin, Ill., a oorporation ofDelaware Application September 26, 1946, Serial No. 699,370

1 Claim.

My invention relates to portable electric air heaters and has for itsobject to provide a relatively simple electric air heater.

An object of my invention is to provide a novel form of resistor and ofmounting thereof for an electric air heater.

Other objects of my invention will either be apparent from a descriptionof several forms of device embodying my invention or will be pointed outin the course of such description and set forth particularly in theappended claim.

In the drawings,

Figure 1 is a view, in front elevation, of a portable electric airheater embodying my invention, with parts cut away,

Fig. 2 is a horizontal, sectional View thereof taken on the line 2--2 ofFig. 1,

Fig. 3 is a Vertical, sectional view thereof taken on the line 3-3 ofFig. 1,

Fig. 4 is a fragmentary horizontal sectional view thereof taken on theline 4-4 of Fig. 1,

Fig. 5 is a fragmentary vertical sectional View taken on the line 5--5of Fig. 4,

Fig. 6 is a view in front elevation of a modified form of heating unitembodying my invention,

Fig. 7 is a view in vertical section taken on the line 1-1 of Fig. 6,

Fig. 8 is a fragmentary view in front elevation of another modication ofheating unit embodying my invention,

Fig. 9 is a View in vertical section therethrough taken on the line 9-9of Fig. 8, and,

Fig. 10 is a view in longitudinal section through a holding means.

Referring first of all to Figs. 1 to 5 of the drawings I have thereillustrated a, portable electric air heater II embodying a base I3 whichmay be made of any suitable or desired molded plastic material whichwill withstand the temperature rise to which it will be subjected. Onbase I3 which may be of any suitableor desired form in molded plastic, Iprovide a, casing comprising end members I5, a rear end closure I'I anda front end closure I9 together with a second opposite end closuremember 2 I. An upper cover 23 is provided with a plurality ofhorizontally-extending slots therein so that a convection stream ofheated air may enter apertures 25 in the lower closure member 21, owupwardly past the sides of heating elements to be hereinafter describedin detail, and out through apertures 29 in the upper cover 23.

My improved heating units 3| include substantially rectangular shapedrelatively thin metal plates which may either be of iron or steel orpreferably of aluminum 33. The thickness of the plates may be .015" or.020. The side edge portions 35 are return-bent over a part of the widthof the plate 33 and a resistor strip 31 is positioned between thefolded-over side edges 35 and the main part of the body of sheet 33 andextending in a zigzag fashion from one end of the sheet 33. Thebent-over portions are pressed against the main portion of plate 33 sothat the resistor strips, 3l will be held in their proper operativepositions.

I provide a plurality of metallic rods 39 extending substantiallyvertically in the casing being held at their lower ends by openings inthe base I3, while their upper ends are fitted into holding members Iwhich 4are made of electric-insulating material and have ascrew-threaded opening i3 therein. The other reduced end portion 45 (seeFig. 10) of holding member 4I is adapted to receive a, capped nut 4iwhich is effective not only to hold the casing in proper operativeassembled position but also to hold the rods 39 in their properoperative positions. The end of terminal portions of resistor 3'I areadapted to be clamped against the reduced center or mid-end portion ofeach of the sheets 33 as by nuts 5I screwed on rod 39.

The casing plates may have their lower edges secured to the base I3 asby short screws 52.

The outer surface of resistor strip 31 may have thereon an integral,inorganic, high-temperature-resisting, heat-conducting andelectric-insulating coating and I may use the method, for instance, setforth in U. S. Patent No. 1,526,127. I may also cover the inner surfaceof plate 33 with such an anodic coating or I may provide such a coatingon either the outside surface of the resistor or on the inside surfaceof the plate.

Referring now to Fig. 6 of the drawings, I have there illustrated aslightly modified form of heating unit embodying a sheet 53 which hasits side edge portions bent around over a resistor strip 55 whichextends in a zigzag fashion from one end of sheet 53 to the other endand which is covered as by a second sheet 51 having return-bent sideedges as shown in Fig. 7 of the drawings.

The assembly of one or more of heating units as shown in Figs. 6 and 7is substantially the same as has already been set forth in combinationwith Figs. l to 5 inclusive.

Referring now to Figs. 8 and 9 of the drawings, I have there illustrateda sheet 59 having round side edges 6I which are adapted to be returnbentto substantially circular shape and to enclose a helcally-Wound resistorconductor 63 p0- 3 sitioned in the bent around edges. The assembly ofone or more of such heating units may be done in substantially the samemanner as was hereinbefore set forth in connection with Figs. 1 to 5inclusive.

While I have already stated that I may use either sheet steel orpreferably aluminum the characteristic of the sheets 33, 53 and 59 isthat the entire outer surface of these sheets may be covered by anintegral, inorganic, heat-conducting, high-temperature-resisting andelectric-insulating coating having a thickness on the order of .001.

I may also cover the entire outer surface of resistor 3l, of resistor55, 0r of resistor 63 with substantially the same coating. The methodused in providing this coating may be substantially that shown in U. S.Patent No. 1,526,127.

While I may provide such an anodic electricinsulating coating having arelatively very slight thickness n the order of .00i on either thecasing or upon the resistor, I may provide a coating on both theresistor and on the casing whereby a much thicker electric-insulatingmaterial is obtained.

Referring now to Fig. 8 0f the drawings, I have there shown that theadjacenthelical turns of the helically-wound round conductor 63 are incontacting engagement with each other, this being possible because ofthe fact that the entire outer surface of the resistance conductor 63 iscovered with an electric-insulating coating. This construction in whichthe adjacent turns of a hellically-wound resistor member are incontacting engagement with each other makes it possible to increase theamount of energy translated into heat in a given area.

Various modifications may be made in the device embodying my inventionwithout departing from the spirit and scope thereof and all suchmodications clearly coming within the scope of the appended claim shallbe considered a, part 0f my invention.

I claim as my invention:

An electric air heater comprising a substantially rectangular casing, aplurality of spaced rods supported by said casing therein, a thinrectangular metal sheet having integral, returnbent edges along itslonger edges, coiled metallic resistance conductors within the returnbends of said edges and held thereby in heat-conducting engagement withsaid sheet, and a thin layer of inorganic, heat-conducting,high-temperature-resisting, electric-insulating material lying betweensaid sheet and coils and being integral with one of them, said metalsheet having integral return-bent portions also at its ends forencircling said rods for supporting said sheet thereon. Y

CLARK M. OSTERHELD.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNITED STATES PATENTS Number Name Dale 768,764 Leonard Aug. 30, 19041,598,753 Spackman Sept. 7, 1926 1,610,116 Woods et al. Dec. 7, 19261,827,508 Cope Oct. 23, 1931 2,357,288 Ricard Sept. 5, 1944 2,362,152Osterheld Nov. 7, 1944

